Filters Reference - ALLEN & HEATH Xone:22 User Manual

The VCF Filters
A voltage controlled filter is an audio filter where the cut-off frequency is altered by a DC
control voltage rather than a variable resistor. This produces a much wider operating
range and more control over the filter response to create unlimited combinations of
tonal effect.
Filter Type Select
The filters provide two simultaneous filter types: high-pass, and low-pass.
illuminated switch selects which type is active.
The graphs below show the effect on the audio frequency response for the two filter
types. The range of sweep from low to high frequency is shown together with the effect
of adjusting RESONANCE.
The vertical scale shows the amount of cut or boost around the normal 0dB operating
level. The horizontal scale shows the change in frequency from low (bass) to high
(treble).
FILTER REFERENCE
LO-PASS FILTER
+ 20
+ 15
+ 10
LO
+ 5
0dB
-5
-10
-15
-20
20 100
HI-PASS FILTER
+ 20
+ 15
+ 10
LO
+ 5
0dB
-5
-10
-15
-20
20 100
HI
1kHz 10k 20k
HI
1kHz 10k 20k
A large
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